1. Field of the Invention
The present invention relates to a barrier film having an extremely high barrier property used as a packaging material for the foods, the medicines and the like, a packaging material and a substrate material for electric devices and the like, a production method therefor, and a laminated material, a packaging container, and an image display medium using the barrier film.
2. Description of the Related Art
Conventionally, as a packaging material having a gas barrier property with respect to the oxygen gas, the water vapor, or the like, and a good storage suitability for the foods, the medicines, or the like, those of various kinds have been developed and proposed. For example, a barrier film comprising a coating layer of a polyvinylidene chloride (PVDC) or an ethylene vinyl alcohol copolymer (EVOH) deposited on a plastic base material has been proposed.
However, according to the gas barrier film, the barrier property with respect to the oxygen and the water vapor is not sufficient. In particular, a problem is involved in that the remarkable deterioration of the barrier property is generated by the high temperature sterilizing process. Furthermore, according to a gas barrier film provided with a coating film of a polyvinylidene chloride (PVDC), the poisonous dioxin is generated at the time of the burning so that the adverse effect to the environment is concerned.
Then, recently, a barrier film comprising a vacuum deposition film of an inorganic substance such as a silicon oxide and an aluminum oxide deposited on a base material film has been proposed. Moreover, a lamination of a resin layer made of an epoxy resin or a mixture thereof, and the above-mentioned vacuum deposition film has been proposed (Japanese Patent Application Laid-Open (JP-A) No. 8-164595).
In contrast, according to electronic devices, for example an image display apparatus such as a flexible display, in the case a barrier film is used as the base material for a plastic film base as a glass base material substitute, or in the case a barrier film is used as a cover film for a solar battery module, a barrier property higher than the barrier property required to the conventional packaging application (for example, a 1.0 cc/m2/day·atm or less oxygen transmission rate, and a 1.0 g/m2/day or less water vapor transmission rate) is required to the barrier film. Moreover, the heat stability and the chemical resistance durable to the high temperature and the various processing chemicals at the time of producing a display element are required to the barrier film. Furthermore, even after providing the product, maintenance of the high barrier property under a severe environment such as a high humidity and heat stability test is required.
Since the conventional gas barrier film provided with a vacuum deposition film of an inorganic oxide such as a silicon oxide and an aluminum oxide has the excellent transparency and it hardly influences the environment, the demand thereof to a packaging material, or the like can be highly expected. However, the barrier properties of the barrier film are still lower than that of the packaging laminated material using an aluminum foil. Moreover, in the case the vacuum deposition film of the inorganic oxide is of a single layer, a problem is involved in that the barrier properties are deteriorated at the time there is omission of the deposition.